Q&A: Bought a car and discovered a defect, when and how to cancel the transaction?

In the case before us, Reuven sold Shimon a car at a price lower than the market value. Before the purchase, both went for an inspection at a garage, and the buyer was told there was a leak in the car that could be fixed with a simple repair (replacing a gasket).

However, after the purchase and payment, the buyer took the car to another garage to fix the leak, where he was told that the engine would die within a few kilometers, meaning the engine was failing. The buyer immediately notified the seller. The seller suggested getting a second opinion from another garage, but there too he was told that the engine was "finished."

The buyer realized that the car wasn't worth the price and therefore asked to cancel the transaction due to the defect. However, while they were sorting out the return of the purchase and refund, the buyer drove the car for an hour and a half to Jerusalem, and admitted in court that he drove the car after learning about the defect.

In our case - the seller wants to uphold the sale while the buyer wants to cancel it. Regarding driving the car, the buyer claims that since his money is still with the seller who is using it, he wanted to use the car.

After hearing both parties and reviewing Shulchan Aruch Choshen Mishpat section 232 paragraph 3, we find:

It states in Shulchan Aruch section 232 that if a defect is found in a purchase and the buyer is not satisfied with it, the purchase is void and the payment must be returned. However, if the buyer uses the item after learning about the defect, the purchase remains valid because the buyer "agreed and accepted" - meaning he agreed to purchase the item despite its defect.

Ramban explained that once the defect is discovered, the purchase is immediately void. The moment the buyer uses the item, since he doesn't want to be considered a thief, he has agreed to the purchase and it can no longer be voided. This is what we ruled according to the Shulchan Aruch mentioned above - that the purchase cannot be canceled because he used the item.

However, one should know that in cases where the buyer had to use the item, such as discovering the defect while in a dangerous location, as the Gemara mentions about a person who bought a horse and while riding in the forest discovered it had no teeth (meaning the horse would die within days since it couldn't eat, which is a defect that justifies canceling the sale), despite discovering the defect in a dangerous place, the buyer can continue using it until reaching a safe place and leave it there to return the purchase.

In cases where the defect is discovered after a significant time, such as a month, even though the purchase can be canceled if it's clear the defect existed at the time of sale, and the purchase is void and the money must be returned, it's clear that the time of usage must be deducted as if the buyer had rented the car or item during the time he used it without knowing about the defect.